JP2002080794A - Filler for coating and flat coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filler for coating capable of attaining homogeneous flatting effect with little addition, a method for manufacturing the same and a coating containing the filler. SOLUTION: The filler for coating is constituted with waterworks-sludge powder having an average particle sizes of 0.5-15 μm. The filler can be prepared by dehydrating, crushing and drying waterworks-sludge followed by pulverization. Further, an aqueous flat coating which contains the filler and an aqueous binder at a ratio of (aqueous binder/filler)=0/1 to 1/2 (by weight) in terms of solid components is stable for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filler useful as an extender of a matte paint and a paint containing the filler (particularly a water-based paint).

[0002]

2. Description of the Related Art Water-based paints usually contain an aqueous binder resin such as a water-soluble resin or a water-dispersible resin, a pigment, a dispersant, and the like. Particularly, in the case of a matte paint, an inorganic filler (matting agent) is used. An extender is incorporated into the paint. As the extender pigment, calcium carbonate, alumina, silica, talc, clay, barium sulfate, silica sand powder and the like are used.

However, the extender does not have a sufficient matting effect, and in order to obtain a high matte effect, it is necessary to incorporate a large amount of an expensive extender and a paint containing a large amount of the extender is required. Inferior in coating film physical properties, weather resistance and chemical resistance.
Further, a paint containing a large amount of extender pigment has low storage stability, and the degree of matting of a coating film obtained over time may change, or a hard precipitate which is difficult to re-disperse may occur.

[0004] In order to stabilize the dispersion of the extender, an emulsifier is also blended as a dispersion stabilizer.
If a large amount of emulsifier is used, the water resistance of the coating film is greatly reduced.

[0005] On the other hand, despite the large amount of water sludge discharged from the water treatment plant, which contains a reusable active ingredient, its disposal becomes difficult year by year. Has become.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a filler for a paint which can provide a high matting effect with a small amount of addition, and a paint containing the filler.

Another object of the present invention is to provide a filler for a coating material having high dispersion stability as well as mattness even if the particle size is large, and a coating material containing the filler.

Still another object of the present invention is to provide a matte paint which is stable for a long period of time.

Still another object of the present invention is to provide a matting paint having excellent water resistance, weather resistance and chemical resistance.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above-mentioned problems of the prior art, and as a result, when using tap water sludge powder as a filler for paint instead of the conventional extender, It has been found that even if the particle size is large, the dispersion stability and the matting property are high, and a high matting effect can be obtained by adding a small amount.

That is, the paint filler of the present invention comprises S
It is composed of water sludge powder mainly composed of iO ₂ and Al ₂ O ₃ . The average particle diameter of the clean water sludge powder is 0.5 to 1
It is 5 μm, particularly preferably about 1 to 5 μm. The paint filler may be obtained by dewatering and drying tap water sludge and pulverizing the same.

The present invention also includes a paint containing the filler, a binder and a solvent (particularly an aqueous solvent). In particular, it is an aqueous matting paint containing an aqueous binder and an extender pigment, and the extender pigment may be composed of the filler. The ratio (weight ratio) of the aqueous binder and the filler was calculated as a solid content, and the aqueous binder / filler = 1
It is about 0/1 to 1/2, particularly preferably about 4/1 to 2/1.

Further, the present invention provides a paint containing an aqueous binder having an average particle diameter of 1 to 5 μm and SiO ₂
And a method of adding a water sludge powder containing Al ₂ O ₃ as a main component to improve dispersion stability or mattness.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION [Paint Filler] The paint filler of the present invention is composed of water sludge powder. Clean water sludge powder is powder obtained from sludge discharged from a water purification plant.

The average particle size of the water sludge powder is 0.5 to 1
5 μm (for example, 1 to 15 μm), preferably 1 to 10
μm (for example, 1.5 to 10 μm), and more preferably about 1 to 5 μm (for example, 1.5 to 5 μm). The tap water sludge powder as the filler of the present invention has a large particle size, not only exhibits excellent matting properties, but also has a dispersibility despite being a powder that has been coagulated and precipitated using a coagulant or the like. high. The filler of the present invention may be subjected to a surface treatment. However, unlike the conventional extender such as calcium carbonate, the filler has excellent dispersion stability and matte effect even without the surface treatment.

The composition of the tap water sludge powder is not particularly limited.
Although not always constant, silica (especially,
SiO ₂ ) and alumina (particularly Al ₂ O ₃ ),
In addition, metal oxides (eg, iron oxide, manganese oxide,
Calcium oxide), organic substances and the like. The content of silica is usually 10 to 50 in sludge powder in terms of solid content.
% By weight, preferably about 20 to 40% by weight, and more preferably about 25 to 40% by weight.
In terms of solid content, it is about 5 to 40% by weight, preferably about 10 to 35% by weight, and more preferably about 15 to 30% by weight in the sludge powder.

The water content of the tap water sludge powder is 10% by weight.
Or less, preferably 5% by weight or less.

The shape of the particles of the tap water sludge powder is not particularly limited, and may be spherical, elliptical, polygonal, or amorphous.

The pH of the tap water sludge powder is not particularly limited.
2 to 13, preferably 3 to 10, more preferably 4 to
It is about 8. The pH of tap water sludge is usually around neutrality, but the pH becomes alkaline when an alkali such as slaked lime is used as a dehydration aid.

[Production Method of Filler for Paint] The filler for paint of the present invention can be obtained by dewatering, drying, and pulverizing the water sludge precipitated using a coagulant.

Specifically, first, sludge (tap water sludge) discharged from a sludge concentration layer of a water purification plant is dewatered in a dehydration step using a dehydrator or a solar drying floor. Next, the dewatered sludge is crushed by a crusher or the like in a crushing step to 10 mm or less, preferably about 0.5 to 5 mm. Further, the crushed sludge is dried in a drying step until the water content becomes 10% by weight or less, preferably 5% by weight or less. By adjusting the water content to 10% by weight or less in the drying step, the particle size can be easily adjusted in the next pulverizing step. In the drying step, for example, it is preferable to dry at a temperature of about 100 to 300 ° C, preferably about 200 to 300 ° C. In the pulverizing step, fine pulverization is performed using a pulverizer or the like to about 0 to several hundred μm. Crushing
It may be performed repeatedly. Then, in the classification step, the average particle diameter is 0.5 to 15 μm, preferably 1
Classify the clean water sludge powder of about 10 to 10 μm, more preferably about 1 to 5 μm.

In the above step, a secondary crushing step, a secondary drying step, a fine pulverizing step and the like may be provided as necessary.
In addition, instead of the dehydration step, the crushing step, and the drying step, a heat treatment step of disinfecting with a heat treatment layer may be provided. In the heat treatment step, for example, it is preferable to sterilize at a temperature of about 50 to 200C, preferably about 70 to 150C.

In the dehydration step, dehydration may be performed using a dehydration aid [for example, Ca (OH) ₂ (slaked lime) or the like] to accelerate dehydration. In addition, it is preferable not to use slaked lime from the viewpoint of particle size control because the smaller the calcium (particularly, calcium carbonate) content is, the easier the pulverization becomes.

Further, in the method for producing a filler of the present invention, it is preferable that the tap water sludge powder obtained in the above step is subjected to a calcination treatment. The firing is performed at a temperature of 600 ° C. or more, preferably 7 ° C.
It is preferable to carry out at a temperature of about 00 to 900 ° C. for 1 hour or more, preferably about 2 to 3 hours. By performing the firing, the stability of the water sludge powder is improved.

[Paint] The paint of the present invention contains the above filler. The paint of the present invention can contain conventional components in addition to the filler, but is preferably used as an aqueous paint containing an aqueous binder. Since the filler has an excellent matting effect, a paint containing an aqueous binder as a main component and using the filler as an extender pigment is excellent as an aqueous matte paint.

The aqueous binder is not particularly limited as long as it has a film-forming property, and may be a water-soluble polymer or a water-dispersible polymer.

Examples of the water-soluble polymer include a cellulose derivative (such as hydroxyethylcellulose), a polymer having a carboxyl group or a sulfonic acid group or a salt thereof [methyl methacrylate- (meth) acrylic acid copolymer,
Methyl methacrylate- (meth) acrylate-
(Meth) acrylic acid copolymer, styrene- (meth) acrylic acid ester- (meth) acrylic acid copolymer, styrene-maleic anhydride copolymer or a salt thereof]. Further, as the salt, ammonium salt, amine salt,
Alkali metal salts and the like.

Examples of the water-dispersible polymer include acrylic resin emulsion, vinyl acetate polymer emulsion (polyvinyl acetate, vinyl acetate-methyl acrylate copolymer, ethylene-vinyl acetate copolymer, etc.), styrene-based Polymers [for example, polystyrene, styrene-methyl (meth) acrylate copolymer, styrene- (meth) acrylate- (meth) acrylic acid copolymer], thermoplastic resins such as thermoplastic polyurethane; epoxy-based Resin (glycidyl ether type epoxy resin such as bisphenol type epoxy resin), thermosetting resin such as amino resin, silicone resin and the like can be mentioned.

Examples of the acrylic resin emulsion include homo- or copolymers of acrylic monomers. Examples of the acrylic monomer include (meth) acrylic acid; C _1-10 alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate; C _3-12 cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate; aryl (meth) acrylates such as phenyl (meth) acrylate; (meth) acryls such as benzyl (meth) acrylate Acid aralkyl esters; hydroxy _C2-6 alkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; alkylamino-alkyl (meth) such as dimethylaminoethyl (meth) acrylate Acrylate; (meth) acrylamide or a derivative thereof; Rishijiru (meth) containing epoxy groups, such as acrylates (meth) acrylate;
(Meth) acrylonitrile and the like. The acrylic monomer may be used in combination with a copolymerizable monomer. Examples of the copolymerizable monomer include an aromatic vinyl monomer (eg, styrene); a fatty acid vinyl ester monomer (eg, vinyl acetate); and an unsaturated polycarboxylic acid (eg, maleic anhydride). And the like, or unsaturated polycarboxylic acid derivatives (eg, dimethyl maleate); olefin-based monomers (eg, ethylene).

A highly adhesive thermoplastic acrylic resin,
In general, a thermosetting acrylic resin is preferably a resin having at least one functional group selected from a carboxyl group, a hydroxyl group, and a glycidyl group.

These binders can be used alone or in combination of two or more. The binder is usually used in the form of an emulsion. Preferred binders include, for example, acrylic resin emulsions, epoxy resin emulsions, urethane resin emulsions and the like, particularly acrylic resin emulsions.

The glass transition temperature of the binder is -20 to 20.
50 ° C., preferably about 0 to 50 ° C., and the film forming temperature of the emulsion is −10 to 30 ° C., preferably 0 to 30 ° C.
It is about ° C.

The ratio (weight ratio) of the aqueous binder to the filler, based on the solid content, is aqueous binder / filler = 10/1 to 1/2, preferably 5/1 to 1/1, more preferably 4/1. It is about 1-2 / 1.

Other components include, for example, dispersants (surfactants such as nonionic surfactants and anionic surfactants), inorganic pigments (white pigments such as titanium oxide, yellow pigments such as chrome yellow, iron oxide red). Red pigments, such as
Orange pigments such as molybdate orange, green pigments such as chrome green, blue pigments such as dark blue, purple pigments such as manganese violet, black pigments such as carbon black, etc., and organic pigments (azo pigments, phthalocyanine pigments, lake pigments, etc.) , Thickeners (polysaccharides such as cellulose derivatives), film-forming aids (cellosolves, carbitols, etc.),
Wetting agents (polyhydric alcohols such as ethylene glycol), cross-linking agents (amino resins such as melamine resin),
Examples thereof include a plasticizer, a surface conditioner, an antifoaming agent, a viscosity modifier, a flame retardant, an antistatic agent, a curing agent, and a water-soluble organic solvent. The ratio (weight ratio) of the aqueous binder and the pigment is usually an aqueous binder / pigment = 10/1 to 1/3 in terms of solid content,
Preferably 5/1 to 1/1, more preferably 3/1 to
It is about 2/1.

The solvent is preferably an aqueous solvent, and examples thereof include water alone and water-miscible solvents [eg, alcohols (ethanol, isopropanol, etc.), ketones (acetone, etc.)] and the like.

As long as the effect of the filler of the present invention is not impaired, extenders such as silica, calcium carbonate, barium sulfate, aluminum hydroxide, aluminum silicate, mica, magnesium silicate, alumina, bentonite, magnesium oxide Etc.) can also be added.

The method for preparing the water-based paint is not particularly limited.
It can be prepared by a conventional method such as mixing, for example, if necessary, add a pigment to water to which a dispersant has been added and stir to prepare a pigment mill base, and then adjust the pigment mill base by adding an aqueous binder and the like. May be.

[0038]

According to the present invention, a filler for a coating material having a uniform matting effect can be obtained with a small amount of addition. Further, the paint containing this filler has a stable matting effect over a long period of time and is excellent in water resistance, weather resistance and chemical resistance. Further, by using the tap water sludge powder as a filler for paint, it leads to effective use of tap water sludge which has been a problem in disposal treatment.

[0039]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, the production examples of the paint fillers used in the examples and the performance evaluation methods of the paints and the coating films in the examples are shown.

(Manufacture Example 1 of Filler for Paint) Sludge discharged from a sludge concentration layer at a water purification plant was dewatered by a dehydrator and crushed by a crusher to 10 mm or less. The crushed sludge was dried at 250 ° C. for about 30 minutes until the water content became 5% by weight or less, and finely pulverized to 10 μm by a pulverizer. further,
After classifying with a classifier, baking at 700 ° C for 3 hours,
Tap water sludge powder A having an average particle size of 1.9 μm was obtained. Table 1 shows the properties of the tap water sludge powder A.

(Production Example 2 of Paint Filler) The sludge discharged from the sludge concentration layer of the water purification plant is converted into a dehydration aid [Ca (O
H) ₂ ] and dehydrated with a dehydrator.
m. The crushed sludge was dried at 250 ° C. for about 30 minutes until the water content became 5% by weight or less, and finely pulverized to 10 μm by a pulverizer. Furthermore, after classifying with a classifier, a baking treatment was performed at 700 ° C. for 3 hours to obtain an average particle diameter of 3.6.
μm tap water sludge powder B was obtained. Table 1 shows the properties of the tap water sludge powder B.

The "%" in Table 1 is "% by weight of solid content". Also, Ig-Loss (Ignition loss)
Is a value for estimating organic matter in water, and is represented by the following equation.

Loss on ignition (%) = Evaporation residue (%) − Ignition residue (%)

[0044]

[Table 1]

[Coating Performance Evaluation Method] (Coating Appearance) The coating appearance was evaluated according to the following criteria.

○: No remarkable thickening, aggregation, gelation, etc. during coating production Δ: Slightly thickening, aggregation, gelation, etc. during coating production ×: Viscosity, aggregation, gelation, etc. during coating production is there.

(Paint Stability) After the paint was left at 50 ° C. for 7 days, the appearance was observed and evaluated according to the following criteria.

：: No precipitation, separation, etc. Δ: Some precipitation, separation, etc. ×: Precipitation, separation, etc.

[Coating Film Performance Evaluation Method] (Coating Film Appearance)
After coating and drying in L), the appearance of the coating film was evaluated according to the following criteria.

：: There is no color unevenness, gloss unevenness, lumps, etc. Δ: There are some color unevenness, gloss unevenness, lumps, etc. ×: Color unevenness, gloss unevenness, lumps, etc.

(Gloss) The 60 ° specular gloss was measured.

(Water resistance) The dried coating film was placed in water at 20 ° C. for 7 minutes.
After immersion for days, the appearance of the coating film was evaluated according to the following criteria.

：: No change in state, no change in adhesion before and after the test. Δ: Slight change in state, slight decrease in adhesion before and after the test. X: Remarkable change in state, and adhesion before and after the test. The drop is large.

(Chemical resistance) The dried coating film was spot-tested with a 0.1% by weight aqueous sulfuric acid solution for 24 hours, and the appearance of the coating film was evaluated according to the following criteria.

：: No change in state, no change in adhesion before and after test. Δ: Slight change in state, slight decrease in adhesion before and after test. X: Remarkable change in state, and adhesion before and after test. The drop is large.

Reference Example 1 A dispersant (Demoll EP, Kao Corporation) was added to 90 parts by weight of water.
And 25 parts by weight of an active ingredient, 5 parts by weight of a polycarboxylic acid type polymer surfactant) and 200 parts by weight of titanium oxide, while stirring at high speed with a high-speed disper to produce a pigment mill base. An acrylic resin emulsion (G-25, Mizutani Paint Co., Ltd.) was added to 295 parts by weight of the pigment mill base.
600 parts by weight, solid content: 50% by weight), 1.5 parts by weight of a thickener (hydroxyethyl cellulose), a film-forming aid (Kyowanol M, manufactured by Kyowa Hakko Kogyo Co., Ltd., 2,2,4-trimethyl-) While adding 30 parts by weight of (1,3-pentanediol monoisobutyrate), the mixture was stirred and mixed with a disper to produce a glossy paint. Table 2 shows the evaluation results of various performances of the paint.

Example 1 A dispersant (Demol EP, Kao Corporation) was added to 90 parts by weight of water.
, 25 parts by weight of an active ingredient, 5 parts by weight of a polycarboxylic acid type polymer surfactant), 200 parts by weight of titanium oxide and 95 parts by weight of tap water sludge powder, and high-speed stirring with a high-speed disper to add a pigment mill base. Manufactured. 390 parts by weight of the pigment mill base was added to an acrylic resin emulsion (G-
25, manufactured by Mizutani Paint Co., Ltd., solid content 50% by weight) 60
0 parts by weight, thickener (hydroxyethyl cellulose)
While adding 5 parts by weight and 30 parts by weight of a film-forming aid (Kyowanol M, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, manufactured by Kyowa Hakko Kogyo Co., Ltd.), the mixture is stirred with a disper. It was mixed to produce a matte paint. Table 2 shows the evaluation results of various performances of the paint.

Example 2 A matte paint was produced in the same manner as in Example 1 except that tap water sludge powder B was used instead of tap water sludge powder A. Table 2 shows the evaluation results of various performances of the paint.

Comparative Example 1 A matte paint was produced in the same manner as in Example 1 except that calcium carbonate (average particle size: 2 μm) was used instead of tap water sludge powder A. Table 2 shows the evaluation results of various performances of the paint.

[0060]

[Table 2]

From the results shown in Table 2, the coatings of Examples 1 and 2 are excellent in coating performance and coating film performance, and show excellent matting effects. On the other hand, the paint of Comparative Example 1 was not matte despite the addition of the same extender pigment as in the Examples, in addition to the lack of sufficient paint stability, water resistance and chemical resistance of the paint film. The effect is not enough.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeo Kikuchi 6-5-30 Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. (72) Inventor Kazuhiko Arai 2-191-1, Tobita-Shi, Chofu-shi, Tokyo Kashima Construction Inside the Technical Research Institute Co., Ltd. (72) Inventor Makoto Imo 2-9-1-1, Tobita-Shi, Chofu-shi, Tokyo Kashima Construction Co., Ltd. (72) Katsunori Nishida 2--17-15 Tsukushima, Chuku-ku, Tokyo Tsukishima Machinery (72) Inventor Tsutomu Mizutani 4-3-90 Nishi-Mikuni, Yodogawa-ku, Osaka-shi F-term in Mizutani Paint Co., Ltd. (reference) 4J037 AA18 AA25 CC00 DD05 DD23 EE25 EE29 EE33 FF02 FF15 FF22 FF25 4J038 EA011 HA166 HA446 KA06 KA08 KA20 NA01

Claims (8)

[Claims] 1. A filler for paint composed of water sludge powder containing SiO ₂ and Al ₂ O ₃ as main components. 2. An average particle size of the tap water sludge powder is 0.5-1.
The paint filler according to claim 1, which has a thickness of 5 µm. 3. A filler composed of tap water sludge powder obtained by dehydrating, drying and pulverizing tap water sludge, having an average particle size of 1 to 5 μm, and removing SiO ₂ and Al ₂ O ₃ . Filler for paints composed of inorganic powder as the main component. 4. A paint containing the filler according to claim 1, a binder, and a solvent. 5. The coating according to claim 4, wherein the solvent is an aqueous solvent. 6. An aqueous matting paint comprising an aqueous binder and an extender pigment, wherein the extender pigment is constituted by the filler according to claim 1. 7. When the ratio (weight ratio) of the aqueous binder and the filler is calculated as solid content, the aqueous binder / filler =
The paint according to claim 6, wherein the ratio is 4/1 to 2/1. 8. A water-based binder containing water-based sludge powder having an average particle diameter of 1 to 5 μm and containing SiO ₂ and Al ₂ O ₃ as a main component is added to a coating material containing an aqueous binder to obtain dispersion stability or mattability. How to improve.